[core] Bugfix: Implement ring buffer with xRingbuffer (#7973)

esphome/core/ring_buffer.cpp

@@ -13,8 +13,8 @@ static const char *const TAG = "ring_buffer";
 
 RingBuffer::~RingBuffer() {
   if (this->handle_ != nullptr) {
-    vStreamBufferDelete(this->handle_);
-    ExternalRAMAllocator<uint8_t> allocator(ExternalRAMAllocator<uint8_t>::ALLOW_FAILURE);
+    vRingbufferDelete(this->handle_);
+    RAMAllocator<uint8_t> allocator(RAMAllocator<uint8_t>::ALLOW_FAILURE);
     allocator.deallocate(this->storage_, this->size_);
   }
 }
@@ -22,26 +22,49 @@ RingBuffer::~RingBuffer() {
 std::unique_ptr<RingBuffer> RingBuffer::create(size_t len) {
   std::unique_ptr<RingBuffer> rb = make_unique<RingBuffer>();
 
-  rb->size_ = len + 1;
+  rb->size_ = len;
 
-  ExternalRAMAllocator<uint8_t> allocator(ExternalRAMAllocator<uint8_t>::ALLOW_FAILURE);
+  RAMAllocator<uint8_t> allocator(RAMAllocator<uint8_t>::ALLOW_FAILURE);
   rb->storage_ = allocator.allocate(rb->size_);
   if (rb->storage_ == nullptr) {
     return nullptr;
   }
 
-  rb->handle_ = xStreamBufferCreateStatic(rb->size_, 1, rb->storage_, &rb->structure_);
+  rb->handle_ = xRingbufferCreateStatic(rb->size_, RINGBUF_TYPE_BYTEBUF, rb->storage_, &rb->structure_);
   ESP_LOGD(TAG, "Created ring buffer with size %u", len);
+
   return rb;
 }
 
 size_t RingBuffer::read(void *data, size_t len, TickType_t ticks_to_wait) {
-  if (ticks_to_wait > 0)
-    xStreamBufferSetTriggerLevel(this->handle_, len);
+  size_t bytes_read = 0;
 
-  size_t bytes_read = xStreamBufferReceive(this->handle_, data, len, ticks_to_wait);
+  void *buffer_data = xRingbufferReceiveUpTo(this->handle_, &bytes_read, ticks_to_wait, len);
 
-  xStreamBufferSetTriggerLevel(this->handle_, 1);
+  if (buffer_data == nullptr) {
+    return 0;
+  }
+
+  std::memcpy(data, buffer_data, bytes_read);
+
+  vRingbufferReturnItem(this->handle_, buffer_data);
+
+  if (bytes_read < len) {
+    // Data may have wrapped around, so read a second time to receive the remainder
+    size_t follow_up_bytes_read = 0;
+    size_t bytes_remaining = len - bytes_read;
+
+    buffer_data = xRingbufferReceiveUpTo(this->handle_, &follow_up_bytes_read, 0, bytes_remaining);
+
+    if (buffer_data == nullptr) {
+      return bytes_read;
+    }
+
+    std::memcpy((void *) ((uint8_t *) (data) + bytes_read), buffer_data, follow_up_bytes_read);
+
+    vRingbufferReturnItem(this->handle_, buffer_data);
+    bytes_read += follow_up_bytes_read;
+  }
 
   return bytes_read;
 }
@@ -49,22 +72,55 @@ size_t RingBuffer::read(void *data, size_t len, TickType_t ticks_to_wait) {
 size_t RingBuffer::write(const void *data, size_t len) {
   size_t free = this->free();
   if (free < len) {
-    size_t needed = len - free;
-    uint8_t discard[needed];
-    xStreamBufferReceive(this->handle_, discard, needed, 0);
+    // Free enough space in the ring buffer to fit the new data
+    this->discard_bytes_(len - free);
   }
-  return xStreamBufferSend(this->handle_, data, len, 0);
+  return this->write_without_replacement(data, len, 0);
 }
 
 size_t RingBuffer::write_without_replacement(const void *data, size_t len, TickType_t ticks_to_wait) {
-  return xStreamBufferSend(this->handle_, data, len, ticks_to_wait);
+  if (!xRingbufferSend(this->handle_, data, len, ticks_to_wait)) {
+    // Couldn't fit all the data, so only write what will fit
+    size_t free = std::min(this->free(), len);
+    if (xRingbufferSend(this->handle_, data, free, 0)) {
+      return free;
+    }
+    return 0;
+  }
+  return len;
 }
 
-size_t RingBuffer::available() const { return xStreamBufferBytesAvailable(this->handle_); }
+size_t RingBuffer::available() const {
+  UBaseType_t ux_items_waiting = 0;
+  vRingbufferGetInfo(this->handle_, nullptr, nullptr, nullptr, nullptr, &ux_items_waiting);
+  return ux_items_waiting;
+}
 
-size_t RingBuffer::free() const { return xStreamBufferSpacesAvailable(this->handle_); }
+size_t RingBuffer::free() const { return xRingbufferGetCurFreeSize(this->handle_); }
 
-BaseType_t RingBuffer::reset() { return xStreamBufferReset(this->handle_); }
+BaseType_t RingBuffer::reset() {
+  // Discards all the available data
+  return this->discard_bytes_(this->available());
+}
+
+bool RingBuffer::discard_bytes_(size_t discard_bytes) {
+  size_t bytes_read = 0;
+
+  void *buffer_data = xRingbufferReceiveUpTo(this->handle_, &bytes_read, 0, discard_bytes);
+  if (buffer_data != nullptr)
+    vRingbufferReturnItem(this->handle_, buffer_data);
+
+  if (bytes_read < discard_bytes) {
+    size_t wrapped_bytes_read = 0;
+    buffer_data = xRingbufferReceiveUpTo(this->handle_, &wrapped_bytes_read, 0, discard_bytes - bytes_read);
+    if (buffer_data != nullptr) {
+      vRingbufferReturnItem(this->handle_, buffer_data);
+      bytes_read += wrapped_bytes_read;
+    }
+  }
+
+  return (bytes_read == discard_bytes);
+}
 
 }  // namespace esphome
 

esphome/core/ring_buffer.h

@@ -3,7 +3,7 @@
 #ifdef USE_ESP32
 
 #include <freertos/FreeRTOS.h>
-#include <freertos/stream_buffer.h>
+#include <freertos/ringbuf.h>
 
 #include <cinttypes>
 #include <memory>
@@ -82,9 +82,14 @@ class RingBuffer {
   static std::unique_ptr<RingBuffer> create(size_t len);
 
  protected:
-  StreamBufferHandle_t handle_;
-  StaticStreamBuffer_t structure_;
-  uint8_t *storage_;
+  /// @brief Discards data from the ring buffer.
+  /// @param discard_bytes amount of bytes to discard
+  /// @return True if all bytes were successfully discarded, false otherwise
+  bool discard_bytes_(size_t discard_bytes);
+
+  RingbufHandle_t handle_{nullptr};
+  StaticRingbuffer_t structure_;
+  uint8_t *storage_{nullptr};
   size_t size_{0};
 };